Air-bearing center-guiding apparatus for supporting and laterally center-guiding webs are generally well-known in the art, of which the following U.S. Pat. Nos. 3,971,496, 4,197,972, 4,288,015 and 4,474,320 are exemplary. Although the apparatus described in these patents provide some lateral center-guiding of webs, the center-guiding force developed is negligible for small displacements when applied to guiding thin webs on the order of 15 mils or less in thickness.
Thus, the general object of the present invention is to provide an improved air-bearing center-guiding apparatus for supporting and guiding a thin web in a noncontacting manner, and particularly to provide guide apertures arranged along the web edges of a specially designed shape whereby a web-guiding force is developed for guiding a web along a central axis to a tolerance of plus or minus 0.001 inch (0.0254 mm).